Please help! Stabilized wood problem!

fitzo said:
There's no secret, except maybe the exact conditions each place uses. The wood is impregnated with a "monomer", the precursor to a polymer. It is called "methyl methacrylate" (MMA). In it's polymerized form it's called poly (methyl-methacrylate) or PMA. I have heard that one place uses two different monomers, but that part's a secret I believe. If MMA is polymerized all by it's lonesome into sheet form PMA, we refer to it as Plexiglas, BTW.

The wood is dried to an optimum moisture content, I believe 7% is maximum, 3% is better. It is then placed in a "bomb", or heavy vaccuum, pressure chamber and covered with the MMA. The wood is then subjected to cycles of vaccuum and pressure (and I think some heat as a consequence). The pressure's important, just like in pressure treated wood. Most of what the vaccuum does is suck air out of the pores in the wood so liquid can take it's place. Pressure forces it into the fibers of the wood. After full impregnation with the monomer, the blocks are removed and set on trays/foil where they are spritzed with an "initiator" (usually a peroxide, guys who tried this at home used Noxynol-9, the acne medicine from the pharmacy) which causes the monomer to polymerize and form large molecules called "acrylic plastics", or PMA.

To understand the difference with "home" methods: the stuff like Minwax Wood hardener and Nelsonite are typically acrylics already polymerized, ground up and then dissolved in solvents. Thus, you saturate the wood and then the solvent dries back out leaving the plastic behind. So, when you stop to think about it, if the solids content of the MW is 30%, 70% acetone and you wet the whole block inside, when it dries out only the 30% solids are left behind, so coverage can't be as thorough as with MMA impregnation.

The big difference? The home stuff "coats" the wood internally, whereas the pro procedures can essentially turn the wood into a big continous block of plastic due to the post-impregnation catalytically initiated polymerization.

Hope someone else understood that besides me. Made perfect sense as I wrote it, but I'm not sure..... :)
Click to expand...

Good explanation! I didn't feel like getting into it in that depth but I guess it's good someone did.

If you haven't used a piece that is stabilized correctly I recommend you do. You can tell the difference right away and it is much easier to finish!
 
Tommegow said:
Sorry for another rabbit trail. Do y'all buy off e-bay or does Staburl/Jim
have a website? Goggle only has the ebay stuff
Click to expand...

www.staburl.com is his website address for his ebay store so basically you are buying off his ebay store. You can always email him personally though and ask him to do a piece for you (more likely to do it if you order in bulk); he's always been a real nice guy and answers his emails fairly promptly for me.

Here is a few pics of a knife I did recently using one of Jim's set of scales; even with the poor pic quality you can tell that the wood is great!

Knife1.jpg


Knife3.jpg


Knife4.jpg
 
I know two stabilizers who add the catalyst to the stabilant before adding the stabilant to the vacuum/pressure chamber.

In my opinion vacuum will achieve complete penetration with many soft woods. However, pressure is also required if you want complete penetration in hard/dense woods.

If you are using a mason or glass jar to vacuum your wood, NEVER ADD PRESSURE or you may be injured.
 
fitzo said:
There's no secret, except maybe the exact conditions each place uses. The wood is impregnated with a "monomer", the precursor to a polymer. It is called "methyl methacrylate" (MMA). In it's polymerized form it's called poly (methyl-methacrylate) or PMA. I have heard that one place uses two different monomers, but that part's a secret I believe. If MMA is polymerized all by it's lonesome into sheet form PMA, we refer to it as Plexiglas, BTW.

The wood is dried to an optimum moisture content, I believe 7% is maximum, 3% is better. It is then placed in a "bomb", or heavy vaccuum, pressure chamber and covered with the MMA. The wood is then subjected to cycles of vaccuum and pressure (and I think some heat as a consequence). The pressure's important, just like in pressure treated wood. Most of what the vaccuum does is suck air out of the pores in the wood so liquid can take it's place. Pressure forces it into the fibers of the wood. After full impregnation with the monomer, the blocks are removed and set on trays/foil where they are spritzed with an "initiator" (usually a peroxide, guys who tried this at home used Noxynol-9, the acne medicine from the pharmacy) which causes the monomer to polymerize and form large molecules called "acrylic plastics", or PMA.

To understand the difference with "home" methods: the stuff like Minwax Wood hardener and Nelsonite are typically acrylics already polymerized, ground up and then dissolved in solvents. Thus, you saturate the wood and then the solvent dries back out leaving the plastic behind. So, when you stop to think about it, if the solids content of the MW is 30%, 70% acetone and you wet the whole block inside, when it dries out only the 30% solids are left behind, so coverage can't be as thorough as with MMA impregnation.

The big difference? The home stuff "coats" the wood internally, whereas the pro procedures can essentially turn the wood into a big continous block of plastic due to the post-impregnation catalytically initiated polymerization.

Hope someone else understood that besides me. Made perfect sense as I wrote it, but I'm not sure..... :)
Click to expand...

thanks much for the explanation fitzo ... :thumbup:
 
Chuck Bybee said:
I know two stabilizers who add the catalyst to the stabilant before adding the stabilant to the vacuum/pressure chamber.

In my opinion vacuum will achieve complete penetration with many soft woods. However, pressure is also required if you want complete penetration in hard/dense woods.

If you are using a mason or glass jar to vacuum your wood, NEVER ADD PRESSURE or you may be injured.
Click to expand...


That's interesting about the catalyst, Chuck! Thanks for telling us. I have to admit I don't have a clue how that would work unless the catalysis is heat activated or two-part. Now I'm intruiged about something I'll never find an answer to! :(:)

Good advice about the glass jars. They are not meant to be vaccuum/pressure vessels despite their use in home canning. I totally second your cautions and always advise against using jars other than on the inside of a proper pressure vessel.

Yeah, yeah, folks, I know a whole bunch of people use them, and many will think to themselves, "Works for me". Sincerely, I wish you continued good luck and success with them. Do yourself a favor and make sure the jar's inside some sort of scattershield like a lidded bucket. Glass implosions are ugly affairs.
 
You must log in or register to reply here.
Back
Top